Hate Dumb: While it's widely accepted as a pretty bad movie, it's not uncommon to see people overreact with childish anger at its mere mention. It may have its flaws, but it's not like it killed anyone.
Hilarious in Hindsight: When Ivy, in her guise as Pamela Isley, is about to kiss (and kill) Commissioner Gordon, she stops and tells him "On second thought, you're way too old for me." At one point in her life, Uma Thurman was married to Gary Oldman, who portrays the younger Gordon during his early career in Christopher Nolan's Batman series.
In the movie, Batgirl defeats Poison Ivy. In reality, Poison Ivy got the last laugh: Uma Thurman was able to salvage her career after this, but Alicia Silverstone...was not. And it wasn't even by choice like Chris O'Donnell, her career just died. See Never Live It Down.
Hollywood Pudgy: While the film averts this by never pointing it out, Alicia Silverstone had noticeably put on weight since her fame peaked, and the press had a field day with it at the time of the film's release.
Ho Yay: Undertones of it are pretty much undeniable between the title characters. Supposedly, George Clooney retroactively claims he played Batman as gay (although it seems more of a Take That against said undertones than anything with truth in it).
Dick Grayson: You're just saying that so I can't kiss her, is that it?
Bruce Wayne: Listen, Dick, it's a poisonous kiss.
Dick Grayson: A poisonous kiss? You don't understand. She understands how I feel.
Bruce Wayne: She has clouded your mind and you're not thinking straight.
Dick Grayson: I am thinking straight. For the first time in a long time.
Pretty much anything that Schwarzenegger says, due to the sheer lameness of his puns.
Never Live It Down: Joel Schumacher has been forever associated with this film during his lifetime, despite his strong resume before the Batman franchise he became a B-List director. He's also frequently Mis Blamed... um, even by himself, apparently, taking full responsibility in interviews for all of its problems ("If you don't like the movie, blame the director" he said at one point). By contrast, the screenwriter Akiva Goldsman had no setbacks at all and even went on to win an Oscar for his script for A Beautiful Mind. Producer Peter MacGregor-Scott is almost completely unknown despite arguably having more to do with the quality of the film than anyone else.
The combination of this film and the equally disastrous The Avengers 1998 knocked Uma Thurman back for a few years. She was eventually able to subvert this, but it took several years and the Kill Bill movies to do so.
Alicia Silverstone and Chris O' Donnell both seemed to drop off the A-list soon after this movie.
O'Donnell's work slowed down by personal choice; he said he had plenty of offers on notable projects, but turned down just about all of them so he could focus on raising his children.
The problem with laying the blame where it belongs (with Warner Bros) is that, given the MASSIVE success of both The Dark Knight Trilogy and Joker, it became unthinkable to blame them for this movie. After all, how can the studio that brought us both the Heath Ledger Joker and the Joaquin Phoenix Joker be the same studio responsible for Bat-nipples and ice puns?
The Problem with Licensed Games: The Play Station got a sandbox-style action game published by Acclaim that was panned for crappy controls; it also featured obviously synthesized renditions of pieces from Elliot Goldenthal's score in the movie. A beat-em-up was also released for the portable Game.Com, and it fared similarly to its 32-bit counterpart with critics.
Snark Bait: Ripping on this film is pretty popular. Many snark sites have dedicated time to it. The film was also nominated for a whopping eleven Golden Raspberry Awards, including Worst Picture, though it only won for Worst Supporting Actress (Alicia Silverstone).
Its presence is all but guaranteed on a "worst Superhero film ever" list, and makes more occasional cameos on generic "Worst Films Ever" lists as well. Cracked.com, however, used this movie's reputation to create a list of "five comic book movies way worse than Batman and Robin"-- most of which are waaay more obscure than Batman and Robin.
Bane especially seems to be a good source of snark, especially when compared to the one played by Tom Hardy in The Dark Knight Rises.
So Bad It's Good: If you go in knowing what to expect, and mine it for the unintentional humor, there can be some silly fun to be had.
NONE of those effects compare to the fact that there are certain scenes in the movie that are just played backwards AND forwards.
Squick: Alfred had a Batsuit made for Barbara... in her exact, form-fitting measurements.
Took the Bad Film Seriously: Michael Gough, despite a very limited screen time, gives a genuinely heartwarming performance as a terminally ill Alfred Pennyworth. It is one of the few things about the movie that can be enjoyed at face value. It helps that he had goodwill built up from his presence in the previous three films.
Villain Decay: This movie takes Bane, one of Batman's most strategically successful enemies in the comics, and turns him into a Pokemon Speaking caveman.
Wangst: Robin seems to spend a good chunk of the movie complaining about something or other.
WTH? Casting Agency: Arnold Schwarzenegger as Mr. Freeze. Schumacher wanted a man who looked like he was "chiseled out of ice," so Arnold was high on his list, but those with familiarity with the source character tend to have this reaction.
Most folks just assumed he was cast because he had a slightly similar accent to the character's portrayals in the Adam West TV series.